Designed for long-battery life, this version only comes
preinstalled, mostly on touchscreen tablets and laptops. It runs
the Start screen and apps, but its limited desktop won’t run
your own Windows programs. To compensate, Windows RT includes
versions of Microsoft Word, Excel, PowerPoint, and OneNote.

Windows 8

Aimed at consumers, this version includes the Start screen,
apps, and a full-featured Windows desktop that can run most Windows
programs.

Windows 8 Pro

Aimed at the small business market, this version features
everything from the Windows 8 version, as well as tools used by
small businesses: encryption, extra networking features, and
similar tools. If you buy a Media Center Pack upgrade, Windows 8
Pro can record TV shows through a TV tuner with Windows Media
Center, as well as play DVDs. (To upgrade Windows 8 to Media
Center, buy a Windows 8 Pro Pack.)

Windows 8 Enterprise

Microsoft sells this large business version in bulk to large
businesses.

Each version in the table contains all the features of the versions preceding it. Windows 8 Pro contains everything found in Windows 8, for example.

Here are some guidelines for choosing the version you need:

If you’re considering a tablet with Windows RT, make sure you realize that it can’t run regular Windows programs. You’re limited to its bundled Office programs and any apps you download from the Windows Store.

If you’ll be using your PC at home, pick up Windows 8 or Windows 8 Pro.

If you need to connect to a domain through a work network — and you’ll know if you’re doing it — you want Windows 8 Pro.

Want to play DVDs or record TV shows with Windows Media Center in Windows 8 Pro? Then pull out your credit card and upgrade online for the Media Center Pack. (To upgrade the consumer-oriented Windows 8 with Windows Media Center, buy the Windows 8 Pro Pack.)

If you’re a computer tech who works for businesses, go ahead and argue with your boss over whether you need Windows 8 Pro or Windows 8 Enterprise. The boss will make the decision based on whether it’s a small company (Windows 8 Pro) or a large company (Windows Enterprise).

Most computers let you upgrade to a more powerful version of Windows 8 from the desktop Control Panel’s System area. (Reach for your credit card before clicking the Get More Features with a New Edition of Windows link.)